Mammals are warm-blooded animals that can be found mostly on land but some of them can also be found at sea. These animals share similar characteristics like having a backbone and hair in their bodies. Only mammals also feed their young with the milk produced in their breasts. Aside from these known characteristics, mammals are very interesting animals because of the following facts:

Fact 1: The biggest mammal lives in the sea instead of on land. The gigantic blue whale is actually a warm blooded mammal and is the largest in the mammalian kingdom reaching to lengths of up to 100 feet and weighing up to 150 tons.

Fact 2: Rodents are the most diverse sub-groups of mammals. The whole mammalian kingdom has more than 5000 species. Rodents like rats and mice contribute almost 2000 species to this total.

Fact 3: Mammals are known to have evolved from reptiles. Some 200 million years ago, reptiles referred to as therapsids were considered as the ancestors of mammals of the present times.

Fact 4: All mammals have four limbs. Scientists also refer to them as tetrapods. Popular animals like cats, dogs, lions, and tigers all have four limbs and they all fall under the mammal classification. Many mammals that live in the sea may seem to have only two limbs but they originally had four and later evolved and developed with only two limbs.

Fact 5: The bumblebee bat specie is classified as the smallest member of the mammalian kingdom. This bat is so small that it only reaches to a little more than an inch in terms of body length and it can weigh only 1-2 grams.

Fact 6: Not all mammals give birth to live offspring. Most people may know of most mammals that give birth this way but some are actually egg-laying. The platypus for example produces their offspring by laying eggs similar to birds and reptiles.

Fact 7: Mammals are considered the most intelligent in the whole of the animal kingdom. Human beings are part of the mammalian group and have the most developed brain systems. Monkeys, pigs, and dolphins are also among the highly intelligent species of animals.

Fact 8: Some mammals are great divers of the sea. Beavers for example can dive into the deep water and even hold their breath for as long as 15 minutes. Beavers live mostly at or near the water and need to dive deep to get food for survival.

Fact 9: Baby giraffes are unlike other young mammals that they tend to behave during their childhood days. Instead of playing and running with other giraffes, the young ones are known to be less active and playful because they conserve energy for their own growth and development.

Fact 10: Camels are known to have humps at their back but actually have straight spines.   These humps in their bodies actually serve as storage space for fat which can be used during periods when there is no food around. Camels are typically used by people during travelling to distant places and need some kind of reserve fuel for energy which is provided by the fat in their humps.